Highly sensitive twist sensor based on tilted fiber Bragg grating of polarization-dependent properties

• The fiber twist sensor is based on the polarization-dependent properties of a tilted fiber Bragg grating (TFBG).
• The sensitivity of 0.299 dB/° is achieved with the torsion angle ranging from 0° to 180°.
• The twist angle can be measured with the matrix without considering the temperature.

The transmission intensity of the tilted fiber Bragg grating (TFBG) is strongly dependent on the polarization properties of the TFBG. The polarization characteristic of the cladding modes can be used for twist measuring. In this paper, a highly sensitive fiber twist sensor is proposed. The transmission intensity on the strong loss wavelength showed a quasi-sin θ changing with the twist angle ranging from 0° to 180° for S- or P-polarized input. A high sensitivity of 0.299 dB/° is achieved, which is almost 17.9 times higher than that of the current similar existing twist sensor. The twist angle can be measured precisely with the matrix.